title: Poly(amidoamine) dendrimers as skin penetration enhancers: Influence of charge, generation, and concentration.
abstract: The study investigates the influence of surface charge, generation and concentration of poly(amidoamine) (PAMAM) dendrimers on skin permeation of a model hydrophilic drug, 5-fluorouracil (5FU). Permeation studies were performed using excised porcine skin in a Franz diffusion cell. Saturated concentration of 5FU in isopropyl myristate was applied on the skin after pretreatment with dendrimers and (14)C labeled 5FU was analyzed using a liquid scintillation counter. The influence of dendrimer surface charge (G4-NH(2), G3.5-COOH, and G4-OH), generations (G2-G6-NH(2)) and concentration (0.1-10 mM of G4-NH(2)) on skin permeation of 5FU were studied. The enhancement in drug permeability coefficient (K(p)) was in the following decreasing order G4-NH(2) > G4-OH > G3.5-COOH. Dendrimer increased the skin permeation by increasing the skin partitioning of 5FU. Transepidermal water loss, skin resistance measurements and ATR-FTIR studies revealed that cationic dendrimers act by interacting with the skin lipid bilayers. Increase in G4-NH(2) concentration did not proportionally increase the skin permeation of 5FU. The 5FU K(p) was inversely related to the molecular weight of the dendrimer. G2-NH(2) dendrimer reduced skin resistance to a greater extent than higher generation dendrimers. Overall, the study showed that lower generation cationic dendrimer is more effective in enhancing the skin permeation of hydrophilic drugs.
authors.affiliation: Department of Pharmaceutical Sciences, College of Pharmacy, South Dakota State University, Brookings, South Dakota 57007, USA. omathanu.perumal@sdstate.edu
authors.forename: Venkata Vamsi K
authors.initials: VV
authors.lastname: Venuganti
authors.forename: Omathanu P
authors.initials: OP
authors.lastname: Perumal
mesh_terms: D000818:Animals; D000964:Antimetabolites, Antineoplastic / Q000008:administration & dosage / Q000493:pharmacokinetics; D050091:Dendrimers / Q000008:administration & dosage / Q000737:chemistry*; D005472:Fluorouracil / Q000008:administration & dosage* / Q000493:pharmacokinetics*; D007166:Immunosuppressive Agents / Q000008:administration & dosage / Q000493:pharmacokinetics; D008970:Molecular Weight; D011073:Polyamines / Q000008:administration & dosage / Q000737:chemistry*; D012867:Skin / Q000378:metabolism*; D012869:Skin Absorption; D017550:Spectroscopy, Fourier Transform Infrared; D055672:Static Electricity; D013552:Swine
chemical_list: D000964:Antimetabolites, Antineoplastic; D050091:Dendrimers; D007166:Immunosuppressive Agents; C531249:Poly(amidoamine); D011073:Polyamines; D005472:Fluorouracil